Puckle was born in London in 1667, although it was not until the 1700s that he started to invent. His first recorded military invention was a sword, although no information regarding it seems to have survived. Later, in 1717, he designed his "Defence gun", which went on to be known as the Puckle Gun, and it was patented and trialed with the British Army a year later. Puckle's gun was a large cannon with a revolving cylinder, which could discharge multiple shots at a far higher rate than any infantryman. Although it reportedly functioned very well, conservative officers in the Army disliked the weapon and it was rejected. Puckle's gun was advertised in several newspapers, but it seems there were little buyers.

Puckle was, like most Englishmen of the period, a Christian, and his religious views seem to have affected his inventions. The Puckle Gun came in two variants, according to the 1718 patent: one which fired regular ammunition, designed for use against Christian enemies, and one which fired square bullets, for use against Muslim Turks. The square bullets supposedly caused a more traumatic wound, resulting in higher pain for the victim. Puckle's patent states that:

"The plate of the Chambers of the Gun for a Ship shooting Square Bullets against Turks" and "For Round Bullets against Christians."